The present invention disclosed herein relates to a method for manufacturing a thin film transistor, and more particularly, to a method for manufacturing a stretchable thin film transistor.
Stretchable electronic devices may maintain an electrical function as it is even though a substrate is expended by stress applied from the outside. Stretchable electronic devices may overcome limitations of bendable and/or flexible devices, and thus be applicable in various fields such as sensor skin for robot, wearable communication devices, internal/attachable bio-devices for human body, next generation displays, and the like.
Such a stretchable electronic device may have a structure in which a metal wire is extended. The metal wire is transferred onto a surface of a pre-strained stretchable substrate, and then the stretchable substrate is shrunk to form a metal wire having a wave form. The metal wire may give stretchability to the electronic device. However, the stretchable electronic device may be limited in stretchability of the metal wire by the intensity of pre-strain initially applied into the substrate. Since the metal wire having the wave form has a complicated manufacturing process when compared to that of a general semiconductor device manufacturing process, it is difficult to apply the metal wire into a device having a large area and secure reliability of the metal wire.
Another stretchable electronic device may include a wire formed of a stretchable material having conductivity instead of a metal. The conductive stretchable material includes conductive materials such as conductive polymers, carbon nanotubes, graphene, and the like. However, the conductive stretchable material has high expending capacity, but high electrical resistance than metals. Thus, it is difficult to form a fine micrometer-sized pattern on the conductive stretchable material.
Further another stretchable electronic device may include a wire having a two-dimensional plane spring shape. The spring-shaped wire is compatible with a general semiconductor device process to reduce manufacturing costs and easily secure reliability, thereby having high conductivity. However, when the spring-shaped wire is expanded, since the deformation of the wire may be locally concentrated into a specific portion of the wire to cause damage of the wire, there is limitation in increasing an extending rate.